Deep Thoughts on What Makes Humans Special

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PROVIDENCE, R.I.-Our special stature among Earth's creatures may
look shaky when considering that humans share 98 percent of our
genes and many behaviors with chimps. Yet human behaviors stand
out by reaching levels of complexity unseen in any other part of
the animal world, according to a neurobiologist.

Seeing humans beyond mechanistic cause-and-effect or animal-like
behaviors can be difficult after a lifetime spent studying
brains and behavior, said Robert Sapolsky, a neurobiologist
and primatologist at Stanford University. But he plunged
wholeheartedly into a keynote talk about human uniqueness during
a brain science symposium here on Wednesday (Oct. 13).

What makes humans special comes in no small part from the sheer
quantity of available brain power – at least 300,000 brain cells
for each neuron in a fruit fly brain. Sapolsky referred to a quip
made by chess grand master Garry Kasparov after being defeated by
IBM's Deep Blue supercomputer: "Sometimes quantity becomes
quality."

Basic biological units such as brain cells remain more or less
the same across species. Yet humans have harnessed their higher
neuron count and
complex brain networks to achieve an unmatched level of
cognitive sophistication.

"We have the same nuts-and-bolts physiology, yet we're using it
in very novel ways," Sapolsky explained.

Taking it to another level

Animals may share characteristics with humans such as politically
motivated aggression, empathy and culture, but humans take them
to a level without parallel among animals.

Bands of chimps regularly patrol their territories to kill any
intruders, conquer the territory of neighboring chimps, and even
wipe out other chimp bands in an act bordering on genocide,
Sapolsky said. By contrast, humans have deployed terrible yet
sophisticated weapons technologies so that a
drone operator sitting at Creech Air Force Base outside Las
Vegas can "rain down hellfire on Mesopotamia [Iraq]" by day, and
then rush out in the evening to a daughter's ballet recital.

Chimps and some other species have also demonstrated "theory of
mind," which allows them to understand the thoughts or
motivations of another creature. But they fall short of humans
when considering secondary theory of mind – understanding what
another person thinks of a third party. Such capabilities allow
humans to enjoy delicious stories with layers of intrigue and
gossip, such as "every Shakespeare play ever written," Sapolsky
said.

Like us, animals such as chimps have shown they can take pleasure
in just anticipating a reward, and will perform an action even if
there is some delay in getting the reward. But no chimp has the
long-range vision of a human to study for the SAT so that he or
she can get into a good college in order to get a good job.

Empathy is also not unknown among chimp troops, as evidenced when
members of a troop groom an "innocent bystander" that was
pummeled by an aggressive alpha chimp. Yet humans can commonly
extend empathy over time and space, even experiencing feeling on
behalf of other species. People can understand the terror in the
eyes of a horse in Picasso's Guernica painting, or even feel
sympathy for the fictional blue-skinned
Na'vi aliens of the 3D film "Avatar."

The uncharted brain

On a darker note, Sapolsky pointed out how the sophisticated
thought processes of humans can also go haywire in ways that defy
imitation in the animal world. Depression stands out as one of
the few big exceptions as a
mental illness that afflicts humans and animals alike.

But plenty more can and does go wrong in the human brain. Some
obsessive-compulsive disorder sufferers ritualistically act out
the same behavior again and again. People with Tourette syndrome
often make uncontrolled noises and curse like sailors.

Even rarer neurobiological problems exist. Patients suffering
from so-called Rapunzel syndrome compulsively seek out and eat so
much hair that it blocks their intestines; acrotomophiliacs can
only experience sexual arousal with amputees; and
apotemnophiliacs try to lop off limbs in the belief that they
deserve to be amputees.

Certainly no chimp or baboon ever suffered from so-called
Jerusalem syndrome, Sapolsky said. The bizarre instances of
temporary insanity almost exclusively afflict devout Christians
on pilgrimage to Jerusalem who tend to be traveling alone,
jetlagged and experiencing disappointment with a modern Jerusalem
that does not resemble their dreamy vision of the Holy Land.
These individuals typically end up wrapping a white sheet around
their naked bodies like a toga and preaching on street corners in
the belief that they are the messiah or an apostle.

Answers to everything and nothing

Some people may still worry about neuroscientists slowly
stripping away the uniqueness of humans and reducing human
motivations and behaviors to equations or chemical formulas. But
Sapolsky suggested two reasons not to worry.

First, explaining everything in purely mechanistic terms would
not diminish our appreciation of classical music composed by
Johann Sebastian Bach or the sight of a leaping gazelle, Sapolsky
said. But he added that the second and more crucial reason to
have no fear is that researchers will never somehow figure out an
answer for everything.

"Every time neuroscience comes up with an answer, it's attached
to 10 new questions, and nine of them are better than the
original," Sapolsky said.

That idea of science being meant to encourage a sense of mystery
rather than cure seemed to infect the audience of scientists and
laypeoplewhen it came time for questions. One person pointed out
that one of the few differences between humans and chimps comes
from the amount of cell division for brain cells, and wondered
about someday getting chimp genes to "crank out a few more orders
of complexity" and boost chimp intelligence.

That's an open possibility, Sapolsky agreed.

The questioner then asked about applying the same procedure to
humans and cranking up our intelligence. Sapolsky didn't miss a
beat.